NAG Library Routine Document

e05zlf  (optget)

1

Purpose

2

Specification

3

Description

4

References

5

Arguments

1:     $\mathbf{optstr}$ – Character(*)Input

On entry: a string identifying the option whose current value is required. See Section 12 in e05saf and e05sbf for information on valid options. In addition, the following is a valid option:

$\mathbf{Identify}$

e05zlf returns in cvalue the (upper-cased) routine name supplied to e05zkf when the optional parameter arrays iopts and opts were initialized.

2:     $\mathbf{ivalue}$ – IntegerOutput

On exit: if the optional parameter supplied in optstr is an integer valued argument, ivalue will hold its current value.

3:     $\mathbf{rvalue}$ – Real (Kind=nag_wp)Output

On exit: if the optional parameter supplied in optstr is a real valued argument, rvalue will hold its current value.

4:     $\mathbf{cvalue}$ – Character(*)Output

Note: the string returned in cvalue will never exceed $40$ characters in length.

On exit: if the optional parameter supplied in optstr is a character valued argument, cvalue will hold its current value. cvalue will also contain additional information for some integer and real valued arguments, as indicated by optype.

5:     $\mathbf{optype}$ – IntegerOutput

On exit: indicates whether the optional parameter supplied in optstr is an integer, real or character valued argument and hence which of ivalue, rvalue or cvalue holds the current value.

$\mathbf{optype}=1$

optstr is an integer valued optional parameter, its current value has been returned in ivalue.

$\mathbf{optype}=2$

optstr is a real valued optional parameter, its current value has been returned in rvalue.

$\mathbf{optype}=3$

optstr is a character valued optional parameter, its current value has been returned in cvalue.

$\mathbf{optype}=4$

optstr is an integer valued optional parameter, its current value has been returned in ivalue. Additional information has been returned in cvalue.

$\mathbf{optype}=5$

optstr is a real valued optional parameter, its current value has been returned in rvalue. Additional information has been returned in cvalue.

6:     $\mathbf{iopts}\left(*\right)$ – Integer arrayCommunication Array

Note: the dimension of this array is dictated by the requirements of associated functions that must have been previously called. This array must be the same array passed as argument iopts in the previous call to e05zkf.

7:     $\mathbf{opts}\left(*\right)$ – Real (Kind=nag_wp) arrayCommunication Array

Note: the dimension of this array is dictated by the requirements of associated functions that must have been previously called. This array must be the same array passed as argument opts in the previous call to e05zkf.

8:     $\mathbf{ifail}$ – IntegerInput/Output

On entry: ifail must be set to $0$, $-1\text{ or }1$. If you are unfamiliar with this argument you should refer to Section 3.4 in How to Use the NAG Library and its Documentation for details.

For environments where it might be inappropriate to halt program execution when an error is detected, the value $-1\text{ or }1$ is recommended. If the output of error messages is undesirable, then the value $1$ is recommended. Otherwise, if you are not familiar with this argument, the recommended value is $0$. When the value $-\mathbf{1}\text{ or }\mathbf{1}$ is used it is essential to test the value of ifail on exit.

On exit: $\mathbf{ifail}=\mathbf{0}$ unless the routine detects an error or a warning has been flagged (see Section 6).

6

Error Indicators and Warnings

$\mathbf{ifail}=11$

On entry, the option in optstr has not been recognized.

$\mathbf{ifail}=41$

On entry, optstr indicates a character optional parameter, but cvalue is too short to hold the stored value. The returned value will be truncated.

$\mathbf{ifail}=61$

The arrays iopts and opts have either not been initialized, have become corrupted, or are not compatible with this option setting routine.

$\mathbf{ifail}=-99$

An unexpected error has been triggered by this routine. Please contact NAG.

See Section 3.9 in How to Use the NAG Library and its Documentation for further information.

$\mathbf{ifail}=-399$

Your licence key may have expired or may not have been installed correctly.

See Section 3.8 in How to Use the NAG Library and its Documentation for further information.

$\mathbf{ifail}=-999$

Dynamic memory allocation failed.

See Section 3.7 in How to Use the NAG Library and its Documentation for further information.

7

Accuracy

8

Parallelism and Performance

9

Further Comments

10

Example